One of the most devastating impacts of European exploration on Native American Indians was the spread of disease. European explorers brought with them diseases such as smallpox, measles, and influenza, to which the Native Americans had no immunity. These diseases spread rapidly through the Native American population, causing widespread death and disruption. In some cases, entire tribes were wiped out by disease. The spread of disease also contributed to the decline of the Native American way of life, as it made it difficult for them to hunt, gather food, and defend themselves against their enemies.